通过发布rake -T，您有以下数据库任务:
rake db:create # Create the database from DATABASE_URL or config/database.yml for the current Rails.env (use db:create:all to create all dbs in the config)
rake db:drop # Drops the database using DATABASE_URL or the current Rails.env (use db:drop:all to drop all databases)
rake db:fixtures:load # Load fixtures into the current environment's database
rake db:migrate # Migrate the database (options: VERSION=x, VERBOSE=false)
rake db:migrate:status # Display status of migrations
rake db:rollback # Rolls the schema back to the previous version (specify steps w/ STEP=n)
rake db:schema:dump # Create a db/schema.rb file that can be portably used against any DB supported by AR
rake db:schema:load # Load a schema.rb file into the database
rake db:seed # Load the seed data from db/seeds.rb
rake db:setup # Create the database, load the schema, and initialize with the seed data (use db:reset to also drop the db first)
rake db:structure:dump # Dump the database structure to db/structure.sql
rake db:version # Retrieves the current schema version number
因此，要发布bundle exec rake db:drop:all，如果您想删除所有迁移，并且假设您只想删除迁移，请删除它们并编写新的migrations.
如果您也想更改型号，请使用rails d model.